Introduction

DL_POLY_2 is designed to accommodate a number of different periodic boundary conditions, which are defined by the shape and size of the simulation cell. Briefly, these are as follows (which also indicates the IMCON flag defining the simulation cell type in the CONFIG File - see 4.1.2):

1. None e.g. isolated polymer in space. (IMCON=0).
2. Cubic periodic boundaries.(IMCON=1).
3. Orthorhombic periodic boundaries.(IMCON=2).
4. Parallelepiped periodic boundaries.(IMCON=3).
5. Truncated octahedral periodic boundaries. (IMCON=4).
6. Rhombic dodecahedral periodic boundaries. (IMCON=5).
7. Slab (X,Y periodic, Z nonperiodic). (IMCON=6).
8. Hexagonal prism periodic boundaries. (IMCON=7).

We shall now look at each of these in more detail. Note that in all cases the cell vectors and the positions of the atoms in the cell are to be specified in Angstroms (Å).